Buying guide for best drill bit sets
Although a drill bit sounds like a simple product, both engineering and chemistry are involved in producing good ones. You can pick up a cheap drill bit set at any hardware store, but it's usually worth spending a few bucks more for a quality product.
The correct drill bit will get the job done more quickly and more accurately. But with all the sizes, materials, and specialist options available, it isn’t always easy to know which drill bit set to buy.
The BestReviews team has been looking at what's available, and which drill bit sets are best at particular tasks. If you’re looking for the right drill bit set for your needs, the following shopping guide is full of helpful advice.
When using wall plugs or anchors, it's important to match drill bit size precisely. Too small and you won't get the anchor in. Too large and it will pull straight back out as soon as any load is put on it.
Drill bit set features to consider
There’s a bewildering array of drill bit sets available, but one important thing to remember is that you want the right drill bit for the job. The right information will make your choice much easier, and that includes two things: what the drill bits are made of and what each drill bit is used for.
Materials
All of these materials will be found in general-purpose drill bit sets. They will cut wood, plastics, aluminum, brass, and fiberglass with varying degrees of effectiveness. Steel, tile, brick, concrete, and glass require different approaches.
-
High-speed steel (HSS) is the most common material for drill bits. It's used for all kinds of cutting tools because it's cheap, relatively tough, and easy to sharpen. HSS is at the core of almost all other drill materials, too.
-
Chrome vanadium steel is used for some drill bits. The chrome resists corrosion, and in combination with vanadium it creates a harder metal than HSS. These bits stay sharper longer.
-
Cobalt is alloyed with HSS to produce very hard drill bits. The cobalt becomes part of the drill bit's structure rather than a coating, so they last much longer. You pay a premium, but these are far and away the best drill for steel and will cut effortlessly through wood, aluminum, fiberglass and most composites.
-
Tungsten carbide (often just called carbide) is a tough ceramic bonded onto the end of an HSS shank. It's normally found on good-quality masonry, tile, and glass drill bits.
Coatings
The important thing with any coated drill bit is the thickness of the coating. We would avoid cheap black oxide or titanium drill bit sets because the surface coating will soon wear through, and all you'll be left with is HSS. Buy from a reputable brand and you should avoid this problem.
-
Black oxide-coated drill bits resist corrosion and are more durable.
-
Titanium-coated drill bits are equally popular and similar in performance to black oxide, but these are gold in color.
- Diamond-coated drill bits are used for two very different tasks: drilling glass and making large holes in concrete and cinder blocks.
Did you know?
Masonry drill bits can be three feet long or more, but you’ll need an SDS or SDS-Plus drill to use them.
STAFF
BestReviews
Types of drill bits
Normally, you'll buy a drill bit set that contains the same type of drill bit in various sizes. However, combination sets are available that offer wood, steel, and masonry drill bits in the same case. It can be a convenient option, but it's important to check that the sizes are those you would use regularly.
Twist drill bits (often called jobber drills) are the most common type of drill bit. These are good all-rounders designed to cut through just about anything except masonry, tile, and glass. A good-quality set of twist drill bits is an invaluable addition to any home tool set.
Spade bits are mostly used to drill large holes in wood. These are flat rather than round, with a central point that acts as a guide and two cutting arms. Spade bits cut quite a rough hole, but these are excellent for jobs like running cable or pipe through studs.
Brad-point bits do a similar job to a spade bit but make a much smoother hole with greater precision. An auger bit is effectively the same thing, but much larger.
Forstner bits and saw-tooth bits are mostly used for wood or composites. Both are effective for making large, smooth holes. Forstner bits can be used to make a flat-bottomed hole – like the kind you need for kitchen cupboard door hinges.
Hole saws have a central drill bit that starts the hole and guides the main body – a round metal tube with a sawtooth or smooth cutting edge. These are used for a variety of materials. HSS versions will quickly cut a large hole in particle board or drywall. Carbide- and diamond-coated versions are used for tile, brick, and concrete.
Masonry drill bits are for all kinds of brick, concrete, cinder block, and so on. These are often of modest diameter, used to make holes for wall plugs and anchors, though they can be up to an inch across and as much as three feet long. Masonry drill bits can be used to cut holes in tile, though tile-specific drill bits are better.
Tile and glass drill bits have a round shank and a flat, often arrow-shaped tip, usually of tungsten carbide.
Step drill bits are a conical shape made up of a number of steps, each a greater diameter than the last. The advantage is that you have the option to drill a variety of hole sizes with the same drill bit. However, each step is relatively shallow, so these only work in sheet materials.
Drill bit set prices
With so many options available to you, a summary of drill bit prices could run to dozens of pages! What's probably more useful is some general guidance. If you buy a cheap drill bit set, you're taking a chance. They might be okay, but cheap steel and masonry drill bits are often worthless. Buy the best you can afford from a reputable brand and you'll save yourself a lot of grief.
You can get a cheap set of jobber drill bits – 10 or 20 pieces – for between $5 and $10. If all you want to do is make a few holes in wooden boards or two-by-fours, they're okay. However, for around $20 you'll get longer-lasting and more versatile black oxide- or titanium-coated drill bits, and that is what we would recommend.
Notably, good-quality cobalt drill bits are considerably more expensive, but you're investing in what are effectively precision tools. These will last many times longer than HSS, so they're worth the money if it's something you use frequently.
The same is true of specialist drill bit sets. If you want to hang a shelf on a ceramic tiled wall, a masonry drill will do the job if you’re careful. If it's what you do all day, a tile drill set will save you time, and you won't risk breaking the tiles.
For your safety
Always wear safety glasses or goggles when drilling. Tiny particles of some materials, such as plastic, might seem harmless but can still damage your eyes.
STAFF
BestReviews
Tips
-
Use a guide when drilling. Large drills can be difficult to keep in place when you start drilling, so it's a good idea to drill a smaller pilot hole first to act as a guide. For large holes in wood, use an appropriate bit with a sharp central guide point built in.
-
Use a lubricant when drilling hard metals. Drilling aluminum and brass is easy, but drilling steel and other hard metals generates a lot of heat. This blunts the drill bit and slows cutting. In industrial settings, a cutting fluid or coolant is used to lubricate the tip. At home, use a multi-purpose oil, like three-in-one, and a slow speed. The drill bit will still get hot, though, so let it rest a while before changing it or you'll likely burn your fingers.
- Secure the material with clamps. Try to avoid holding a workpiece with one hand and drilling with the other. If the drill catches – whether in wood or steel – it can spin the material and cause a nasty injury. Whenever possible, use a vise or clamps to hold the material firmly against a benchtop or other secure surface.
Handheld drills are extremely versatile tools, but for a higher degree of accuracy, consider investing in a drill press.
FAQ
Q. What is TiN coating?
A. TiN is titanium nitride, a ceramic. It reduces friction and keeps drills sharper longer. As a result, it’s used on drill bits for cutting metal, although it's fine for wood and plastics. It isn’t recommended for use with aluminum. It cuts fine, but the aluminum shavings stick to it and are difficult to remove. Titanium nitride drill bits vary in quality (coating thickness), so always buy from a recognized brand. They’re invariably a gold color, but not all gold drill bits are TiN, so make sure before ordering.
Q. Can I resharpen carbide-tipped drill bits?
A. All drill bits can be resharpened, but because carbide is so hard, an ordinary grinding wheel won't do. You need a diamond wheel. Sharpening is a tricky process, so you should think about getting a drill sharpening jig for your grinder, or a stand-alone drill bit sharpener. There are several available that will sharpen all kinds of drill bits and can be set for different tip angles. They're not cheap, but if you use a lot of drill bits, they can be economical in the long term.
Q. Is the drill bit's tip angle important?
A. General-purpose drill bits have a tip angle of 118°, good for cutting “soft” materials like wood, brass, and fiberglass. They can be used in plastics, but if you drill this material a lot, it's worth investing in sharper 90° bits. A flatter tip – 135° – is better for hard materials like stainless steel.
